Selection has been studied mainly in genetics but of course there is much more to selection than just genetical selection. In psychology for example trial-and-error learning is simply learning by selection. In chemistry, selection operates in a recrystallisation under equilibrium conditions, with impure and irregular crystals dissolving and pure, well-formed crystals growing. In paleontology and archaeology selection especially favours stones, pottery, and teeth and greatly increases the frequency of mandibles among the bones of hominid skeletons. In linguistics selection unceasingly shapes and reshapes phonetics grammar and vocabulary. In history we see political selection in the rise of Macedonia Rome and Muscovy. Similarly economic selection in private enterprise systems causes the rise and fall of firms and products. And science itself is shaped in part by selection with experimental tests and other criteria selecting among rival hypotheses.This is from Price's posthumously-published 1995 manuscript, "The Nature of Selection". Price went on to lament the lack of a proper theory of selection and the lack of a proper definition of selection. He compared the current state of selection theory with the state of information theory in 1922. Price died in 1975 and apparently this paper was written in 1971 - which makes it ahead of its time indeed. Extensive quotes from "The Nature of Selection" are available free online - in the paper George Price's Contributions to Evolutionary Genetics.
While things have moved on a bit since 1970s the theory of selection is still little known. Evolutionary theory should cover it - but hardly anyone seems to realize that the theory applies to physical systems like crystals in the way that Price clearly indicated. Evolutionary theory is still in an immature state, where it isn't applied through much of its rightful domain. Progress is pretty treacle like: Darwinism has a pretty huge inertia. Also there are fragmented areas of science that are part of the study of selection that are scattered all over the place. Observation selection seems to be studied mostly by physicists and links to evolutionary theory are mostly ignored. Selection bias and sampling effects are concepts which are widely used in science - but again, these topics are rarely seen as being in the domain of evolutionary theory.